#
# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

@Engine("psql");

Move("a", "b");
Move("b", "a");
Move("b", "c");
Move("c", "d");

Win(x, stable: !~ Win(x)) :- Move(x, y), ~Win(y);

ActuallyWin(x) :- Win(x, stable: true);

Test(..r) :- ActuallyWin(..r);